As is known in the art, air traffic control (ATC) is a service that promotes the safe, orderly, and expeditious flow of air traffic. Safety is principally a matter of preventing collisions with other aircraft, obstructions, and the ground, assisting aircraft in avoiding hazardous weather, assuring that aircraft do not operate in an airplane where operations are prohibited, and assisting aircraft in distress. Orderly and expeditious flow assures the efficiency of aircraft operations along the routes selected by the operator.
As is also known, air traffic control services are provided by air traffic control (ATC) systems. An air traffic control system is a type of computer and display system that processes data received from air surveillance radar systems for the detection and tracking of aircraft. Air traffic control systems are used for both civilian and military applications to determine the identity and locations of aircraft in a particular geographic area.
It is desirable in aircraft control systems to store data recorded, obtained, or otherwise provided by, the air traffic control system. In particular, it is desirable to be able to store and play back display data, including images shown on the display system of the air traffic control system. It is desirable to be able to record and play back air traffic control data in case of accident, for teaching purposes, for simulation purposes and the like.
Conventionally, there are several ways to record ATC display data. One technique is to use a video recorder to store ATC display data at each ATC display station. While this approach does not interrupt system operation (i.e., it has no impact on computer code or system performance and thus is a transparent recording technique), the video recorder approach has several drawbacks. For example, there is a relatively large amount of display data to store. If videotapes are used for storage, a relatively large number of videotapes are required to store all of the necessary display data associated with a period of time (e.g., 24 hours). Also, there are typically multiple ATC stations/terminals at which storage is desired. Thus, multiple video recorders or other recording devices are required. Furthermore, it is relatively time consuming to locate a specific location on a videotape during playback of the display data.
Another technique for transparently storing data is to provide computer code used in ATC systems having instructions for sending messages to a storage device, which identify to the storage device the operations being performed by the ATC system. The messages can be sent to the storage device either before or after a corresponding operation is performed. To playback what has occurred in the ATC system, the storage device sends the stored messages to the ATC system and the ATC display system carries out the messages.
However, if the developer of the computer code fails to include code to store a certain step or operation, or if the developer fails to include code to playback a certain message, then the record or playback will not be accurate. Another problem with this approach is that it is necessary to process a relatively large amount of data. Also, it is very expensive in terms of code development because it is very time consuming to include all of the additional computer code to store and play back the operations being displayed on the display system.
It would, therefore, be desirable to overcome the aforesaid and other disadvantages.